Thawing apparatus



(No Model.)

W. E.. HARRIS. THAWING APPARATUS.

Patented Feb. 22

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same, as is plainly indicated in Fig. 1.

UNITED STATEs PATENT OFFICE.

WILLIAM E. HARRIS, OF CHICAGO, ILLINOIS.

THAWING APPARATUS.

, SPECIFICATION forming part. of Letters Patent No. 599,606, dated February 2.2, 1898. Application tiled September 18, 1897. Serial No. 652,137. (No model.)

To all whom t may concern.'

Be it known that I, WILLIAM E. HARRIS, of Chicago,in the county of Cook and State of Illinois, have invented a new and Improved Thawing Apparatus, of which the following is a full, clear, and exact description.

The object of the-invention is to provide a new and improved apparatus for thawing frozen ground, to permit of conveniently working shafts and tunnels in such ground.

The invention consists principally of a shield to be used in' connection with a furnace or other heat-producing apparatus, and designed to direct and retain the heat upon the face of an excavation in frozen soil and to render access to said face obtainable without removing the device.

The invention also consists of certain parts and details and combinations ofthe same, as will be fully described hereinafter and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming a part of this sp'ecilication, in which similar characters of reference indicate corresponding parts in all the figures.

Figure lis a sectional side elevation of the improvement as applied. Fig. 2 is a plan View of the grate for the furnace. Fig. 3 is a face viewof the shield, with parts in section; and Fig. 4 is a sectional plan view of the same on the line 4 4 of Fig. 3.

The improved thawing apparatus is provided with a furnace A, having the conical wall of its tire-box Aformed by a coil of pipe B, the outside of which is covered by alayer of clay C, having a shell C inclosing the The upper end of the furnace A is provided with 'a suitable uptake C2 for the escape of the smoke and gases arising from the burning fuel vheld on a grate D, forming the bottom vof the fire-box and discharging the ashes,

cinders, and the like into an ash-pit E. The upper end B of the coil of pipe B extends through the uptake C2 to connect outside of,

the furnace with a blower or like device F for forcing air through the coil of pipe and heating the air by the burning fuel on the grate D. The lower end B2 of the coil of pipe B is insulated in a box G, containing sand, clay, or like nonheat-conductin g material, the pipe end B2 extending down through ashaft H into the tunnel II to be formed in .the frozen ground.

The end of the pipe B2 in the tunnel connects with a sleeve I, held on a shield I, set against the ground at the end of the tunnel, as indicated in Fig. l, the said shield being provided with a hollow frame I2, into which opens the sleeve I', so that the heated air passing through the coil of pipe B can pass into the hollow frame. A door I3 is hinged onthe said frame I2, and registering apertures I4 and I5,- formed in the adjacent walls of the frame and door, (see Fig. 3,) allow the heated air to pass from the hollow frame I2 into the hollow .door I2, and perforations I6 in the rear face of the door allow the hot air to pass directly in contact with the frozen ground against which theV shield is placed. A suitably-constructed jack .I serves to hold the said shield in position in the tunnel.

Now when the device is in operation and fuel is burning on the grate D in thefurn'ace A and the blower F forces air through the pipe B then this air is heated and passes in this condition into the hollow frame I2 and into the hollow door I3, to iinally issue through the perforations I6 against the frozen ground, so as to thaw the same. When this has been done, the jack J is removed and the door I3 is opened to permit a miner to get at the thawed-out ground in front of the shield, so as to loosen and remove this ground through the open door.' When the ground has been removed, the shield I is moved forward into another part of the tunnel, and then the jack 'J is again applied and air is forced through the hollow frame I2 and .its closed door to repeat the above-described operation. The end B2 of the pipe B is lengthened as the work progresses, so as to make at all times a proper connection with the shield.

In order to prevent radiation of heat from the shield, I prefer to cover the front thereof with wood I7 or other similar material.

It is understood that the heat from the frame I2 thaws out suiiicient ground'in the immediate neighborhood of the frame to allow of removing this ground when the door I2 is opened.

Having thus described my invention, I

IOO

on the said frame and in Communication with the said frame, to allow theheated air to pass from the frame into the door, said door being provided at its inner facing with apertures for the exit of the heated air to the ground against which the shield rests, substantially as shown and described.

VILLIAM E. HARRIS.

Vitnesses:

J. A. MACPHERSON, MARTHA MAoPHERsoN. 

